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Biomedical subjects

H Newesely

Publications and source records attributed to H Newesely.

At least 37 records · Page 2Linked to original sources
PubMed1980

The material science of calcium phosphate ceramics.

Tricalcium, tetracalcium phosphate and hydroxyapatite ceramics exhibit distinct differences in their chemical and structural composition. Only hydroxyapatite ceramic is identical with the original bone mineral. Different preparation methods lead to compact hydroxyapatite ceramic or to porous material with interconnecting macropores as structural equivalents of the spatial structure of cancellous bone. Concerning the behaviour in a biological environment, high crystallinity and large material density result in resistance to dissolution and long lasting stability. Amorphous ultrastructure and porous formation enhance interface activity and bone ingrowth, but also biological degradation of the ceramic implant material.

Biomechanical Phenomena↗
PubMed1979

[Review of implantation materials].

The use of nonmetalic, ceramic materials has led to encouraging developments. Some metal implants have proved to be more reliable in general practice in respect to the mechanics and statics; part of the developmental goal however should include compound materials. Metal implants, tolerated by the organism under favorable conditions, were not accepted as well as the ceramic material. Recently, the long-term prognosis therefore has been viewed with reservation. Even though the tensile values were favorable, the mechanical properties were good, and the corrosion rate in terms of adequate tissue tolerance was generally satisfactorily low for metal, the organism still responded to metal as a foreign body.

Biocompatible Materials↗
PubMed1977

[Natural fluorides. The distinction between technically produced and naturally occurring fluorides in caries prophylaxis].

In the controversial discussion of the bio-availability of fluoride in caries prophylaxis by fluoridation, fluorides coming from the geochemical circulation to the biochemical circulation are sometimes differentiated from synthetic fluorides introduced into fluoride medication. The question as to whether such a differentiation is essential can be answered from the physical-chemical point of view. This requires a wide field of scientific research starting with geochemistry and the knowledge of fluoride deposits, sedimentology, hydrology, technology of inorganic and organic fluorine compounds, thermodynamics of dissolved fluorides, up to biocrystallography and biochemistry of fluorine.

Biological Availability↗
PubMed1975

[The damage caused by caustic acids during sealing of the dental enamel].

The chemical etching of enamel required for adhesion of sealant layers on the dental surfaces means that the enamel structure is weakened, especially due to the fact that after application of the sealant the cauterized layers are no longer in a remineralization equilibrium with the dental environment. The reactions on which cauterization is based are critically discussed. Newly developed synthetics are mentioned whose application as a sealant renders previous cauterization of the enamel by acids superfluous.

Calcium Phosphates↗
PubMed1975

[Lead and arsenic resorption in the hard tissues (crystallochemical studies)].

Histologic-analytical observations on the resorption of lead and arsenic compounds are put into relationship with crystal-chemical analogies in the composition of hard tissue and the structure of calcium phosphate apatites with lead and arsenic substitution. Chemical analyses and x-ray diffraction of calcium and lead apatites with phosphate and arsenate represented as mixed precipitates in solution equilibrium show that - with the exception of calcium arsenate apatite - linear diadochocinetic substitution conditions are existing. The composition of calcium arsenate apatite is clearly shown to contain much less arsenic. This result is explained by the crystallographic laws of substitution in the crystal lattice (diadochocinetic laws). The clinical and physiological findings in lead and arsenic resorption are confirmed by the found distributional equilibria.

Apatites↗